In 1922 he stood at the highest point on Everest, a feat not bettered for 30 years. He invented the predecessor to the puffer jacket and pioneered the use of oxygen in climbing. A World War I hero whose skills also helped save London from burning to the ground during the Blitz of World War II, he was a renowned scientist who was personally chosen by Nehru, the first Indian prime minister, to help lead his nation into the modern world.

She is the author of "Blood and Roses", winner of the English Association's Beatrice White Prize, and presents BBC Radio 4's "Making History". She is a fellow of Sidney Sussex College, Cambridge University, and lives in London.